CVE-2026-18967
Keycloak-services: keycloak-services: saml onetimeuse assertion replay in idp-initiated broker flow
CVSS Score
6.4
EPSS Score
0.0%
EPSS Percentile
0th
A flaw was found in the SAML broker component of Keycloak, an identity and access management solution. When configured as a SAML broker using the IdP-Initiated flow, Keycloak fails to enforce the OneTimeUse condition in SAML assertions. This allows an attacker who captures a valid, unused assertion to replay it multiple times. Successful exploitation could allow an attacker to hijack a user's session and gain unauthorized access to the system as that user.
| CWE | CWE-294 |
| Vendor | red hat |
| Product | red hat build of keycloak |
| Published | Aug 6, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N Attack Vector
Adjacent
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
Red Hat / Red Hat Build of Keycloak
All versions affected Red Hat / Red Hat Build of Keycloak
All versions affected Red Hat / Red Hat Build of Keycloak
All versions affected Red Hat / Red Hat JBoss Enterprise Application Platform Expansion Pack
All versions affected Red Hat / Red Hat Single Sign-On 7
All versions affected References
Credits
Red Hat would like to thank Lidor Vasker for reporting this issue.